1. Field of the Invention
The present invention relates to a mechanism for mounting a detector head including a collimator onto a supporting structure of a radiation detector. The detector head is for example, a camera head of an Anger-type scintillation gamma camera or an x-ray detector head of an x-ray detecting device.
2. Description of the Prior Art
The choice of collimator to be used with a detector head of a radiation detector, in particular for medical diagnostic procedures, depends on the energy level of the radiation. Low energy collimators, for example, may be approximately 80 lbs. lighter than medium energy collimators. Due to that the detector head, which is pivotally mounted onto the supporting structure of the radiation detector, has to be balanced for collimators with different weights with respect to different pivot axes.
U.S. Pat. No. 4,438,335 (Meeder) describes a detector head mounting apparatus, wherein for balancing purposes and dependent on the weight of a collimator a selection is made between at least two different trunnion axes on the detector head in a manner that rotation of the head together with the collimator attached to the head occurs about the trunnion axis which passes nearest to the center of gravity of the head and collimator.
A similar detector head mounting mechanism is depicted in the commonly-owned patent application Ser. No. 555,100, entitled "Detector Head Mounting Mechanism" filed on Nov. 25, 1983 by Anatoly I. Gosis and Frank J. Bartos.
The Japanese laid-open patent application No. 54-154388 (Suzuki) illustrates a detector head mounting mechanism for a scintillation camera, which comprises a shiftable balance weight inside the detector head to match the centroid of the detector head to the center of rotation for collimators having different weights.
U.S. Pat. Nos. 4,101,779 (Schmedemann) and 4,365,343 (Grady et al.) finally describe x-ray apparatus wherein up and down movements of an x-ray source are balanced by shifting of suitable balance weights.